1. Field of the Invention
This invention relates to cleaning compositions suitable for use in cleaning hard surfaces in a household environment, in particular, the cleaning of tile surfaces. More particularly, the cleaning compositions are suitable for use in removing lime soap soil, commonly referred to as "soap scum".
Although there are many known cleaning compositions for hard surfaces, alternative formulations are desirable. There is a particular need for cleaning compositions directed to removing soap scum build-up from such surfaces.
Soap scum build-up is a problem encountered particularly in bathrooms and kitchens with ceramic tile. Typically, removal of the scum requires a rubbing or wiping of the surface after treatment with the cleaning composition. Penetrating beneath the scum and removing the build-up is the most desired method of removal. Formulating a cleaning composition for such penetrating action is difficult, however, because many compositions leave an undesirable smearing or streaking effect on the tile after cleaning.
2. Prior Art
A number of compositions have been suggested for possible use in removing soap scum. Many of these require high concentrations of active ingredients and/or solvent systems containing multiple ingredients. Others require the use of ingredients which, as noted above, leave behind a solid residue, thus necessitating a rinsing step. A dilute aqueous solution which provides for easy removal of soap scum would be advantageous.
U.S. Pat. No. 4,501,680 discloses a liquid detergent composition for cleaning ceramic tiles to remove soap scum, without eroding the grout between such tiles. The disclosed formulations include partially neutralized glutaric and phosphoric acids and, as a detergent, a condensation product of ethylene oxide and linear alcohols having from 8 to 20 carbon atoms.
U.S. Pat. No. 4,581,161 discloses a hard surface cleaner with possible application to removal of soap scum. The composition is also an acidic composition, having at least one C.sub.5 -C.sub.7 dicarboxylic acid and an organic solvent which is preferably an alkylene or polyalkylene glycol.
U.S. Pat. No. 4,587,030 is directed to a foamable cleaning composition useful for removal of soap scum and other household soils. It contains an acidic component comprising a mixture of a weak organic acid and a weak inorganic acid, an amine oxide surfactant, and a co-solvent to reduce surface tension and maintain the composition in a stable mixture.
U.S. Pat. No. 4,960,533 discloses a silicone-based hard surface cleaner suitable for removing soap scum. In addition to two required silicone components, the composition contains glutaric acid.
U.S. Pat. No. 5,439,609 discloses a composition particularly effective for removing soap scum which also imparts residual protection to the cleaned tile. The composition comprises a siloxane block polymer, an ethoxylate-based surfactant, solvents and chelating agents.
International Patent Publication No. WO97/09407 discloses dilute hard surface cleaners effective to remove soap scum. The cleaners comprise a carboxylic acid, a detersive surfactant and, unless the detersive surfactant is a tertiary amine oxide in which the longest alkyl group has from 6 to 12 carbon atoms, an organic solvent which causes the composition to form a clear mixture. As in most of the prior art discussed above, this cleaning composition is in the acid pH range.
International Patent Publication No. WO97/09412 discloses a cleaning composition suitable for removing soap scum. The compositions comprise a detersive surfactant and, unless the surfactant is a tertiary amine oxide in which the longest alkyl group has from 6 to 12 carbon atoms, also an organic solvent which causes the composition to form a clear mixture. In a preferred embodiment, the composition contains bleach.
Many of the prior art compositions are effective in removing soap scum and some of them are also effective in controlling mold and mildew, which often accompany soap scum. However, these compositions generally contain high amounts of active ingredient and/or require the use of special solvents and, as a result, they are relatively expensive to produce. It would be advantageous to develop a hard surface cleaner which would be particularly effective in removing soap scum and which contains low levels of active ingredients.